Crystal chemical characteristics of ellestadite-type apatite: implications for toxic metal immobilization

Dalton Trans. 2014 Nov 14;43(42):16031-43. doi: 10.1039/c4dt02088j.

Abstract

The ellestadite apatites Ca10[(SiO4)x(PO4)6-2x(SO4)x]Cl2 were studied by powder X-ray and neutron diffraction to establish baseline crystallographic data. These synthetic materials, unlike mineral specimens that are well equilibrated, show no Si/P/S ordering and conform to P63/m symmetry. Phosphate-rich ellestadites where 0 ≤ x ≤ 1 show chemical stability towards Toxicity Characterization Leaching Procedure (TCLP) testing and are potential immobilization matrices for mixed toxic metal wastes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apatites / chemistry*
  • Chlorine / chemistry
  • Hazardous Waste
  • Metals, Heavy / chemistry
  • Microscopy, Electron, Transmission
  • Neutron Diffraction
  • Phosphorus / chemistry
  • Powder Diffraction
  • Silicon / chemistry
  • Solubility
  • Spectroscopy, Fourier Transform Infrared
  • Sulfur / chemistry
  • Waste Management
  • X-Ray Diffraction

Substances

  • Apatites
  • Hazardous Waste
  • Metals, Heavy
  • Phosphorus
  • Chlorine
  • Sulfur
  • Silicon